How to Create an Incremental Backup of a UFS Snapshot (ufsdump)

Backing up a UFS snapshot incrementally means that only the files that have
been modified since the last snapshot are backed up. Use the ufsdump
command with the N option. This option specifies the file system device name
to be inserted into the /etc/dumpdates file for tracking incremental dumps.

The following ufsdump command specifies an embedded fssnap command to create an
incremental backup of a file system.

In this example, the -o raw option is used to display the name of
the raw device instead of the block device. By using this option, you
make it easier to embed the fssnap command in commands (such as the
ufsdump command) that require the raw device instead.

Verify that the snapshot has been backed up.

# ufsrestore ta /dev/rmt/0

How to Back Up a UFS Snapshot (tar)

If you are using the tar command to back up the snapshot, mount
the snapshot before backing it up.

Become superuser or assume an equivalent role.

Create a mount point for the snapshot.

For example:

# mkdir /backups/home.bkup

Mount the snapshot.

# mount -F ufs -o ro /dev/fssnap/1 /backups/home.bkup

Change to the mounted snapshot directory.

# cd /backups/home.bkup

Back up the snapshot with the tar command.

# tar cvf /dev/rmt/0 .

Restoring Data From a UFS Snapshot Backup

The backup created from the virtual device is essentially just a backup of
what the original file system looked like when the snapshot was taken. When
you restore a file system from the backup, restore as if you
had taken the backup directly from the original file system. Such a restore
uses the ufsrestore command. For information on using the ufsrestore command to restore
a file or file system, see Chapter 25, Restoring UFS Files and File Systems (Tasks).